, 1887-09-10
70 tho Edisor Of msasto. G6roit Aois.a

given by Mr.. ], IL. Quin on the subject of
Hurricanes. He stated that the basis of
the subject was to be: found in the force
of gravity. He remarked that If Il child
were asked why theibit o flpaper lie held
inh his hand dropped down as soon as he
LET, GO, of it, the. answer ,would be ''because
it is natural for it to do so;"a and, with the
characteristic modesty Of the realty scienti-
ACT mind, iIheJ declared THAT not even
Newton could have given o. truer answer.
That famous observer, of, a falling apnle
certainly discovered something, of the
natural laws of the force of gravity, butthe
term meant what the child would call
weight. Weight on Earth meant that every
thing upon it is attracted by. it towards its
centre, ant why this is so no scientist can
determine" There is -heitherlup nor down,
considered in this way; for whatiS apaInong
us.in Santa Cruz is doWn among our anti
podians at the other side of the globe, ,..n
The air is a fluid pressing with weight
-uuppoitii the Earth, we dont feel its pressure
any more than q crab crawling at the bot
tom of our harbour feels the weight of the
fluid sea over him Yet, just like water,
the air has q certain depth all round the
globe. Balloons have assembled six miles
in it. and perhaps may go higher some day.
The lecturer, then exhibited a simple APP
paratus which he had made to prove that
the air has weight. Promising II little
about a pair If scales, he produced q
white board to which two equal glass
tubes were perpendicularly attached,
communicating at their bases by Il pipe.
Into one he poured cOlOured water, which
of course rose to an equal height III
both. By a piston he withdrew the
air above the water in the first tube,
whereup0II The water assembled therein,
being forced up from the other tube by the
weight of the air pressing upon the open
surface there. Similarly, said he, in the
lamp. OF the desk before him the hot
lighlened air above the flame assembled,
being driven by the colder and denSer air
outside, pressing through the apertures
below Thus also wind currents We're
caused. In and about any locality where
the air of the atmosphere has been heated,
wind win be generated, and there will be
sI6ted a fall iii the barometer. This instru-
ment was then explained i'll detail.
He had prepared two large diagrams TO
show the isobars, or rings of equal bar0-
metrical pressure over a portion OF Europe
around any such depression, or location of
aerial disturbance. He mentioned that the
existence of these isobars liz concentric
circles had been ascertained by systematic
observations of the height of the barometer
at various surrounding localities, regularly
reported to certain stations, as Paris, Lou
don, Copenhagen, where they are marked
upon the map. Such discoveries have
been of practical value, especially in the
United States, in giving warning of APP!
proacbilig storms. For it is not be sup:
posed, that a centre of, depression remains
stationary,-it travels along a path, bring
ing the storm to different locations success
Sisely. osass g ~ Htu afH4b 1d ~
Near the two diagrams referred to he had
posted two plaza, ds in letters a foot high
summing up fthe rationale of the winds
action In Cyclone and Anti-cyclOne re-.
specifically. 80 7i' i,aH 80 #i'' ~
q COOLING to the most interesting part Of
his subject, viz! local hurricanes, the leo.
tnrer explained IL third big diagram of the
visit of a cyclone to our island, giving illus.
trations of several that have occurred in
recent years. S+4 9'5 ~ iItti.tti
tItis now well known that these tropical
cyclones are vast whirlwindS from so to 500
miles in diameter, revolving the more RI.
pidly and dangerously the nearer their
centre, whiclsi is itself per tectly calm. This
calm Or deadtiocikN results from the force of
the wind OPPOSING irselfat 1hat point. The
place of this entire of rotation, together
wlth0 the swhirIwind Grounds Jadyanees
Steadily 8aloug \ Certain fixed track with a
speed varying from two to forty miles an
hour. The general track Of W~est~Indian
80 - l. ~ IVY